Battery pack power supply system and battery pack power supply method

ABSTRACT

The present disclosure provides a battery pack power supply system and a battery pack power supply method. The battery pack power supply system comprises: a first battery set and a second battery set; a switch control circuit connected with electronic switches, to control the first battery set and the second battery set to be connected in series or in parallel; and a main control chip connected with the first battery set, the second battery set, and the switch control circuit, respectively, to control the electronic switches to be open or closed to discharge the first battery set and the second battery set; a wake-up circuit connected with the main control chip, to wake up the entire battery pack power supply system; a USB circuit connected with the first battery set, the second battery set, and the main control chip, respectively, to output power for charging an external device under the control of the main control chip; and a self-locking circuit connected with the switch control circuit, to disable the electronic switches when the switch control circuit is prohibited.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims the benefit of priority to Chinese PatentApplication No. CN 2020105168945, entitled “BATTERY PACK POWER SUPPLYSYSTEM AND BATTERY PACK POWER SUPPLY METHOD”, filed with CNIPA on Jun.9, 2020, the disclosure of which is incorporated herein by reference inits entirety.

FIELD OF TECHNOLOGY

The present disclosure provides a battery pack power supply system and abattery pack power supply method.

BACKGROUND

At present, in the battery pack industry, to extend the universality ofa battery pack, two groups of batteries are connected in series orparallel to form a dual-voltage battery pack (hereinafter referred to asbattery pack). The battery pack provides two voltage specifications topower an electric tool. Commonly used battery packs include 20V/40Vbattery packs, 24V/48V battery packs, and 40V/80V battery packs.

There are two methods to switch between series connection and parallelconnection of two groups of batteries: an electronic switch method and amechanical structure method. The electronic switch method is achieved bythree controlled electronic switches. In the mechanical structuremethod, series or parallel connection of two groups of batteries isachieved by a female tab abutting against an electric tool or charger.If the female tab connects positive and negative poles of a group Abattery and a group B battery together, then the two groups of batteriesform a parallel relationship; and if the female tab connects thenegative pole of the group A battery to the positive pole of the group Bbattery, and power is output from the positive pole of the Group A andthe negative pole of the Group B, then the two groups form a seriesrelationship.

A traditional dual-voltage lithium battery pack simply provides power toan electric tool, but cannot achieve many other functions.

In view of this, there is indeed a need to improve existing batterypacks to make them applicable in more scenarios.

SUMMARY

An object of the present disclosure is to provide a battery pack powersupply system and a battery pack power supply method. The battery packpower supply system not only can supply power to an electric tool, butalso can directly charge an external device such as a mobile phone,which extends the use of a battery pack.

To achieve the above object, the present disclosure provides a batterypack power supply system, including: a first battery set and secondbattery set; a switch control circuit connected with electronicswitches, to control the first battery set and the second battery set tobe connected in series or in parallel; a main control chip connectedwith the first battery set, the second battery and the switch controlcircuit, respectively, to control the electronic switches to be open orclosed to discharge the first battery set and the second battery set; awake-up circuit connected with the main control chip, to wake up theentire battery pack power supply system; a USB circuit connected withthe first battery set, the second battery set and the main control chip,respectively, to output power for charging an external device under thecontrol of the main control chip; and a self-locking circuit connectedwith the switch control circuit, to disable the electronic switches whenthe switch control circuit is disabled.

As an improvement of the present disclosure, the electronic switchesfurther include a first switch, a second switch and a third switch; whenthe main control chip controls the first switch and the second switch tobe closed and the third switch to be open, the first battery set and thesecond battery set are connected in parallel with each other; and whenthe main control chip controls the first switch and the second switch tobe open and the third switch to be closed, the first battery set and thesecond battery set are connected in series with each other.

As an improvement of the present disclosure, the battery pack powersupply system further includes a housing and a circuit boardaccommodated in the housing, wherein the first battery set and thesecond battery set are both accommodated in the housing, and the switchcontrol circuit, the main control chip, the wake-up circuit, the USBcircuit and the self-locking circuit are all formed on the circuitboard; and the housing is provided with an extended power outputinterface connected to the USB circuit and a cover plate for coveringthe extended power output interface, the cover plate being slidablyarranged to expose or cover the extended power output interface.

As an improvement of the present disclosure, the wake-up circuitincludes a microswitch wake-up circuit, the microswitch wake-up circuitincluding a microswitch, and when the cover plate slides to expose theextended power output interface, the cover plate synchronously triggersthe microswitch, such that the entire battery pack power supply systemis woken up.

As an improvement of the present disclosure, the wake-up circuit is abuttoned wake-up circuit, the buttoned wake-up circuit including abutton provided on the housing, and the entire battery pack power supplysystem is woken up after the button is pressed.

As an improvement of the present disclosure, the USB circuit is providedwith a step-down component and a current-limiting component to performvoltage step-down and current-limiting operations on a voltage outputfrom the battery pack power supply system, a voltage after the step-downand current-limiting operations being output to charge the externaldevice.

As an improvement of the present disclosure, the self-locking circuit isconfigured such that the switch control circuit is not controlled by themain control chip when the switch control circuit is automaticallylocked.

As an improvement of the present disclosure, the battery pack powersupply system further includes a first analog front-end connected inparallel with the first battery set and a second analog front-endconnected in parallel with the second battery set; the first analogfront-end is connected with the main control chip to collect a voltageof the first battery set and transmit the voltage to the main controlchip; and the second analog front-end is connected with the main controlchip to collect a voltage of the second battery set and transmit thevoltage to the main control chip.

As an improvement of the present disclosure, when the voltages of thefirst battery set and second battery set are lower than a certain value,the main control chip disables the USB circuit to stop charging theexternal device and controls the entire battery pack power supply systemto shut down.

As an improvement of the present disclosure, the battery pack powersupply method further includes a communication isolation circuit, whichis connected to the second analog front-end at one end and to the maincontrol chip at the other end, so that the second analog front-endcommunicates with the main control chip in a bidirectional isolationmanner through the communication isolation circuit.

To achieve the above object, the present disclosure further provides abattery pack power supply method applied to a battery pack power supplysystem, the battery pack power supply system including a main controlchip, a first battery set and a second battery set, a switch controlcircuit, a wake-up circuit, a USB circuit and a self-locking circuit.The battery pack power supply method mainly includes the followingsteps:

S1, inserting an external device USB charging cable into an extendedpower output interface of the battery pack power supply system, suchthat the external device USB charging cable is brought into electricalconduction with the USB circuit of the battery pack power supply system;

S2, the wake-up circuit waking up the entire battery pack power supplysystem;

S3, the main control chip controlling the switch control circuit, suchthat the first battery set and the second battery set are connected inseries or in parallel and the first battery set and the second batteryset are discharged; and

S4, the main control chip enabling the USB circuit, such that the USBcircuit outputs power to charge an external device.

As an improvement of the present disclosure, the battery pack powersupply system further includes a housing and a circuit boardaccommodated in the housing; the first battery set and the secondbattery set are both accommodated in the housing, and the switch controlcircuit, the main control chip, the wake-up circuit, the USB circuit andthe self-locking circuit are all formed on the circuit board; theextended power output interface is provided on the housing and connectedto the USB circuit; and the housing is further provided with a coverplate for covering the extended power output interface, the cover plateslidably arranged to expose or cover the extended power outputinterface.

As an improvement of the present disclosure, the wake-up circuit furtherincludes a microswitch wake-up circuit, the microswitch wake-up circuitincluding a microswitch, and step S2 is specifically: when the coverplate slides to expose the extended power output interface, the coverplate synchronously triggering the microswitch such that the entirebattery pack power supply system is woken up.

As an improvement of the present disclosure, the wake-up circuit is abuttoned wake-up circuit, the buttoned wake-up circuit including abutton provided on the housing, and step S2 is specifically: waking upthe entire battery pack power supply system when the button is pressed.

As an improvement of the present disclosure, the switch control circuitis further electrically connected with electronic switches, theelectronic switches including a first switch, a second switch and athird switch; when the main control chip controls the first switch andthe second switch to be closed and the third switch to be open, thefirst battery set and the second battery set are connected in parallelwith each other; and when the main control chip controls the firstswitch and the second switch to be open and the third switch to beclosed, the first battery set and the second battery set are connectedin series with each other.

As an improvement of the present disclosure, the battery pack powersupply method further includes the following steps:

S5, when the main control chip detects no charging current in the USBcircuit, disabling the USB circuit; and

S6, when the main control chip detects that a charging current of theUSB circuit is greater than a certain value, enabling the USB circuitand continuing detecting the charging current of the USB circuit.

As an improvement of the present disclosure, the USB circuit is furtherprovided with a step-down component and a current-limiting component toperform voltage step-down and current-limiting operations on a voltageoutput from the battery pack power supply system, a voltage after thestep-down and current-limiting operations being output to charge theexternal device; and the self-locking circuit is connected with theswitch control circuit, such that the switch control circuit is notcontrolled by the main control chip when the switch control circuit isdisabled.

As an improvement of the present disclosure, the battery pack powersupply system further includes a first analog front-end connected inparallel with the first battery set and a second analog front-endconnected in parallel with the second battery set; the first analogfront-end is connected with the main control chip to collect a voltageof the first battery set and transmit the voltage to the main controlchip; and the second analog front-end is connected with the main controlchip to collect a voltage of the second battery set and transmit thevoltage to the main control chip.

As an improvement of the present disclosure, the battery pack powersupply method further includes: step S7, the first analog front-end andthe second analog front-end respectively detecting the voltages of thefirst battery set and the second battery set in real time, and when thevoltages of the first battery set and second battery set are lower thana certain value, the main control chip disabling the USB circuit to stopcharging the external device and controlling the entire battery packpower supply system to shut down.

As an improvement of the present disclosure, the battery pack powersupply method further includes a communication isolation circuit, whichis connected to the second analog front-end at one end and to the maincontrol chip at the other end, so that the second analog front-endcommunicates with the main control chip in a bidirectional isolationmanner through the communication isolation circuit.

The present disclosure has the beneficial effects: on the one hand, withthe USB circuit provided in the present disclosure, voltage step-downand current-limiting operations may be performed by the USB circuit onthe voltage output from the battery pack power supply system, such thatthe voltage after the step-down and current-limiting operations may beused to charge an external device such as a mobile phone, so the batterypack may be applied in more scenarios; on the other hand, theself-locking circuit is provided such that when the switch controlcircuit is disabled, the electronic switches fail and are no longercontrolled by the main control chip due to the self-locking circuit,thereby protecting the entire battery pack power supply system isprotected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a structure diagram of a first embodiment of a battery packpower supply system of the present disclosure.

FIG. 2 is an exploded diagram showing mutual cooperation between amicroswitch and a cover plate.

FIG. 3 is a three-dimensional structure diagram of a contact tab of anelectric tool.

FIG. 4 is an exploded diagram of FIG. 3.

FIG. 5 is a working principle diagram of a self-locking circuit in FIG.1.

FIG. 6 is a flow diagram of a battery pack power supply methodcorresponding to FIG. 1.

FIG. 7 is a structure diagram of a second embodiment of a battery packpower supply system of the present disclosure.

FIG. 8 is a flowchart showing a battery pack power supply methodcorresponding to FIG. 7.

DETAILED DESCRIPTION

To make the object, technical solutions and advantages of the presentdisclosure clearer, the present disclosure will be described in detailbelow in conjunction with the accompanying drawings and specificembodiments.

As shown in FIGS. 1 to 4, the present disclosure provides a battery packpower supply system applied to a battery pack. The battery pack powersupply system includes a housing (not shown), and a first battery set11, a second battery set 12 and a circuit board (not shown) accommodatedin the housing, the circuit board being electrically connected with thefirst battery set 11 and the second battery set 12, and the circuitboard being formed with a switch control circuit, a main control chip(MCU), a wake-up circuit, a USB circuit and a self-locking circuit.

The housing is provided with an extended power output interface 20connected to the USB circuit and a cover plate 30 for covering theextended power output interface 20, the cover plate 30 being slidablyarranged to expose or cover the extended power output interface 20.Specifically, the extended power output interface 20 is a USB interfacematched with the USB circuit, and the cover plate 30 includes a coverpart 31 that covers the extended power output interface 20 and a triggerpart 32 that extends backward from the cover part 31.

The first battery set 11 and the second battery set 12 may be connectedin series or in parallel, and then may output two types of operatingvoltages to supply power to electric tools with different demands. Ofcourse, when the battery pack power supply system itself is not chargingand not connected to an electric tool, the first battery set 11 and thesecond battery set 12 may also output voltages through the extendedpower output interface 20 to charge an external device such as a mobilephone. In this case, the first battery set 11 and the second battery set12 may be connected in series or in parallel, depending on the actualsituation. In the present disclosure, whether the battery sets areconnected in series parallel mainly depends on the voltage demand of thecorresponding external device detected by the USB circuit.

The switch control circuit is connected with electronic switches, tocontrol the first battery set 11 and the second battery set 12 to beconnected in series or in parallel; and the main control chip (MCU) isconnected with the first battery set 11, the second battery set 12 andthe switch control circuit, respectively, to control the electronicswitches to be open or closed to discharge the first battery set and thesecond battery set. Specifically, the electronic switches include afirst switch KEY1, a second switch KEY2, and a third switch KEY3; whenthe main control chip (MCU) controls the first switch KEY1 and thesecond switch KEY2 to be closed and the third switch KEY3 to be open,the first battery set 11 and the second battery set 12 are connected inparallel with each other; and when the main control chip (MCU) controlsthe first switch KEY1 and the second switch KEY2 to be open and thethird switch KEY3 to be closed, the first battery set 11 and the secondbattery set 12 are connected in series with each other.

The self-locking circuit connected with the switch control circuit todisable the electronic switches KEY1-KEY3 (i.e., the electronic switchesKEY1-KEY3 are all turned off) when the switch control circuit isprohibited, and at that time, the switch control circuit is no longercontrolled by the main control chip (MCU). It is to be noted that theevent that “the switch control circuit is prohibited” usually occursafter the battery pack power supply system is installed to the electrictool, and when the extended power output interface 20 is not covered andcan be used normally, the battery pack and a contact tab 40 of theelectric tool abut against each other, and to prevent a short circuit ofthe first battery set 11 and the second battery set 12, the switchcontrol circuit needs to be automatically locked, and at that time, theswitch control circuit is no longer controlled by the main control chip(MCU).

Specifically, the contact tab 40 includes a base 41 and male tabs 42disposed on the base 41, the male tabs 42 including a first male tab421, a communication male tab 422, a connection male tab 423, and asecond male tab 424 arranged successively along a length direction ofthe base 41, each of the first male tab 421, the second male tab 424 andthe connection male tab 423 including two connection tabs 420 arrangedside by side, an extension direction of the connection tabs 420 beingperpendicular to the length direction of the base 41. When the batterypack power system is inserted into the electric tool, abutting terminals(not shown) in the battery pack directly selectively abut against theconnection tabs 420 of the first male tab 421, the second male tab 424and the connection male tab 423, and the communication male tab 422, toachieve series and parallel connection of the first battery set 11 andthe second battery set 12.

The self-locking circuit is based on a structural and electronicmechanism, and is equivalent to a switch; the moment the abuttingterminals in the battery pack abut against the contact tab 40, an effectequivalent to switch closure is achieved, and the abutting terminals arebrought into electrical conduction with the contact tab 40; at thistime, the contact tab 40 disables the electronic switches, such that theelectronic switches KEY1-KEY3 are all opened and no longer operate, andthe series and parallel connection of the first battery set 11 and thesecond battery set 12 is only controlled by the contact tab 40 at thistime.

Specifically, as shown in FIG. 5, a contact tab 1, a contact tab 2, acontact tab 3, and a contact tab 4 s are provided in a tab holder of theself-locking circuit, and the 4 contact tabs correspond to positive andnegative poles of Group B and Group B batteries, respectively, whereinthe contact tab 1 corresponds to the positive poles (B+) of the Group Bbatteries, the contact tab 2 corresponds to the positive poles (A+) ofthe Group A batteries, the contact tab 3 corresponds to the negativepoles (B−) of the Group B batteries, and the contact tab 4 correspondsto the negative poles (A−, which is also reference ground GND of themain control chip MCU) of Group A batteries. The contact tab 4 and acontact tab 5 are key devices of the self-locking circuit.

Since the switch control circuit and the switch circuit of each of theelectronic switches KEY1-KEY3 are the same, only one of the switches isexplained as an example here. In FIG. 5, MCU_GPIO_x is connected to anoutput pin of the main control chip MCU. When MCU_GPIO_x outputs a highlevel, Q1 is turned on, thus Q2 and Q3 are also turned on, and thecorresponding electronic switch is closed; and when MCU_GPIO_x outputs alow level, Q1 is turned off, thus Q2 and Q3 are also turned off, and thecorresponding electronic switch is opened; therefore, the closing andopening of the electronic switch are determined by the high and lowlevels output by MCU_GPIO_x.

The contact tab 4 in the tab holder is grounded, and the contact tab 5is connected to the junction of R2 and R1. When the contact tab 40 ofthe electric tool or charger is inserted into the tab holder, the maletab 42 causes a short circuit of the contact tab 4 and the contact tab5, i.e., a short circuit of R2; and at this time Q1 is no longercontrolled by the main control chip MCU, the electronic switchesKEY1-KEY3 are all opened and no longer operate, and the series andparallel connection of the first batter 11 and the second battery set 12is only controlled by the contact tab 40.

Of course, the above description of the specific structure of thecontact tab 40 is only exemplary, and those skilled in the art can makechanges according to the actual situation.

The main control chip (MCU) is configured to control the entire batterypack power supply system, and the wake-up circuit is connected with themain control chip (MCU), to wake up the entire battery pack power supplysystem. In this embodiment, the wake-up circuit includes a microswitchwake-up circuit and a buttoned wake-up circuit, the microswitch wake-upcircuit including a microswitch 13, and when the cover plate 30 slidesto expose the extended power output interface 20, the cover plate 30synchronously triggers the microswitch 13, such that the entire batterypack power supply system is woken up.

The microswitch 13 includes a switch body 131 and a terminal (not shown)accommodated in the switch body 131 and electrically connected to acircuit board, the terminal being electrically connected to the firstbattery set 11 and the second battery set 12 through the circuit board.The microswitch 13 also includes a contact point (not marked) providedon the switch body 131, and a rectangular contact piece 132, wherein oneend of the contact piece 132 is fixed to the switch body 131 and theother end thereof is a free end; the contact point is located on aninner side of the contact piece 132 and close to the fixed end of thecontact piece 132; the contact piece 132 repeatedly touches the contactpoint of the microswitch 13 in a lever-like manner; an elastic member(not shown) is provided between the contact piece 132 and the switchbody 131; when the contact piece 132 presses the contact point throughthe trigger part 32, the terminal is brought into conduction; and whenthe contact piece 132 leaves the contact under the action of the elasticmember, the contact point returns to an untriggered state, and theterminal is brought out of conduction. The trigger part 32 is preferablya plate-like structure, which aids the trigger part 32 in pushing thecontact piece 132 to rotate.

The microswitch wake-up circuit is configured to power up the batterypack and the USB circuit at the same time, so that the battery pack andthe USB circuit are woken up synchronously; and the buttoned wake-upcircuit is configured to wake up the battery pack, while the USB circuitis selectively woken up according to the actual situation. When thebattery pack power supply system is not working, if one wants to checkthe charge of the battery pack, s/he does not need to plug in a USBcharging cable or trigger the microswitch 13; instead, s/he can simplypress a button on the battery pack housing and check the charge usingthe buttoned wake-up circuit, which is convenient and safe.

The USB circuit is connected with the first battery set 11, the secondbattery set 12, and the main control chip (MCU), respectively, to outputpower for charging an external device under the control of the maincontrol chip (MCU). It may be understood that, with the development ofexternal devices, charging interfaces of external devices haveaccordingly developed into several types, including the following commonones: Mini USB interfaces, Micro USB interfaces (including 2.0 and 3.0),and Type series interfaces (including Type-A, Type-B and Type-C). TheUSB circuit in the present disclosure may be may be configured tocorrespond to one of the aforementioned types of interfaces, or it maybe configured to be standard USB2.0 or USB3.0, and then an adapter isused for adaptation, so long as the external device (including a mobilephone, computer, printer, or display) can be charged.

The USB circuit is provided with a step-down component (such as atransformer, not shown) and a current-limiting component (such as aDC-DC voltage-regulating and current-limiting chip, not shown) toperform voltage step-down and current-limiting operations on a voltageoutput from the battery pack power supply system, such that a voltageafter the step-down and current-limiting operations may be output tocharge the external device. Of course, when the main control chip (MCU)detects no charging current flowing through the USB circuit, the USBcircuit is directly disabled, and the entire battery pack supply systemshuts down 1 minute later.

The battery pack power supply system further includes a first analogfront-end 14 connected in parallel with the first battery set 11 and asecond analog front-end 15 connected in parallel with the second batteryset 12; the first analog front-end 14 is connected with the main controlchip (MCU) to measure the real time voltage of the first battery set 11and transmit the voltage to the main control chip (MCU); and the secondanalog front-end 15 is connected with the main control chip (MCU) tomeasure the real time voltage of the second battery set 12 and transmitthe voltage to the main control chip (MCU). Of course, when the voltagesof the first battery set 11 and second battery set 12 are lower than acertain value, the main control chip (MCU) disables the USB circuit tostop charging the external device and controls the entire battery packpower supply system to shut down, to wait for charging.

The first analog front-end 14 communicates with the main control chip(MCU) through a first communication channel 16, so that when the maincontrol chip (MCU) needs to measure the voltage of any cell in the firstbattery set 11, the first communication channel 16 may be used totransmit an instruction, and the first analog front-end 14, uponreceiving the instruction, quickly detects and extracts the voltagevalue of the corresponding cell, and then converts the voltage valueinto a digital signal and sends the digital signal to the main controlchip (MCU) through the first communication channel 16.

The battery pack power supply system further includes a communicationisolation circuit 17. The communication isolation circuit 17 isconnected to the second analog front-end 15 at one end and to the maincontrol chip (MCU) at the other end, so that the second analog front-end15 communicates with the main control chip (MCU) in a bidirectionalisolation manner through the communication isolation circuit 17, andthen information of the second analog front-end 15 is controlled andread. In some embodiment, the second analog front-end 15, thecommunication isolation circuit 17 and the main control chip (MCU)communicate with each other through a second communication channel 18,and for the specific communication process, reference may be made to thecommunication process between the first analog front-end 14 and the maincontrol chip (MCU) described above.

As shown in FIG. 6, the present disclosure further provides a batterypack power supply method applied to the aforementioned battery packpower supply system, which mainly includes the following steps:

S1, flicking the cover part 31 of the cover plate 30 such that the coverplate 30 slides, and inserting an external device USB charging cableinto the extended power output interface 20 such that the externaldevice USB charging cable is brought into electrical conduction with theUSB circuit;

S2, when the cover plate 30 slides to expose the extended power outputinterface 20, the trigger part 32 of the cover plate 30 synchronouslytriggering the contact point of the microswitch 13, such that the entirebattery pack power supply system is woken up;

S3, when the main control chip (MCU) detects the microswitch 13 istriggered, the main control chip (MCU) controlling the switch controlcircuit to close the first switch KEY1 and the second switch KEY2, suchthat the first battery set 11 and the second battery set 12 areconnected in parallel, or to close the third switch KEY3, such that thefirst battery set 11 and the second battery set 12 are connected inseries, and at this time, the first battery set 11 and the secondbattery set 12 are discharged;

S4, the main control chip (MCU) enabling the USB circuit, such that theUSB circuit outputs power to charge the external device;

S5, when the main control chip (MCU) detects no charging current in theUSB circuit, disabling the USB circuit;

S6, when the main control chip (MCU) detects that the charging currentof the USB circuit is greater than a certain value, enabling the USBcircuit and continuing detecting the charging current of the USBcircuit; and

S7, the first analog front-end 14 and the second analog front-end 15continuously detecting voltages of the first battery set 11 and thesecond battery set 12 in real time, and when the voltages of the firstbattery set 11 and second battery set 12 are lower than the certainvalue, the main control chip (MCU) disabling the USB circuit to stopcharging the external device and controlling the entire battery packpower supply system to shut down.

Of course, this embodiment is mainly applicable when the battery packpower supply system is not put into an electric tool, in which case, theUSB circuit may be used to charge an external device such as a mobilephone; and after the battery pack power supply system is plugged into anelectric tool, the extended power output interface 20 is covered andcannot be used, and at the same time, the battery pack power supplysystem and the contact tab 40 of the electric tool abut against eachother, to achieve series or parallel connection of the first battery set11 and the second battery set 12, and at this time the switch controlcircuit is disabled (i.e., automatically locked), and the self-lockingcircuit causes a failure in the electronic switches KEY1-KEY3.

FIG. 7 shows a second embodiment of the battery pack power supply systemof the present disclosure. Compared with the first embodiment shown inFIG. 1, this embodiment mainly differs in that the microswitch wake-upcircuit is omitted, and the extended power output interface 20 may alsobe used to charge an external device after the battery pack power systemis plugged into an electrical tool.

In this embodiment, the wake-up circuit is a buttoned wake-up circuit,the buttoned wake-up circuit including a button (not shown) provided onthe housing, such that the entire battery pack power supply system iswoken up after the button is pressed. Other identical structures (suchas the switch control circuit, the self-locking circuit, the USBcircuit, the main control chip MCU, the first analog front-end 14, thesecond analog front-end 15, and the communication isolation circuit 17)are not described.

As shown in FIG. 8, a battery pack power supply method in thisembodiment mainly includes the following steps:

S1, flicking the cover part 31 of the cover plate 30 such that the coverplate 30 slides, and inserting an external device USB charging cableinto the extended power output interface 20 such that the externaldevice USB charging cable is brought into electrical conduction with theUSB circuit;

S2, pressing the button such that the entire battery pack power supplysystem is woken up;

S3, when the main control chip (MCU) detects the button is triggered,the main control chip (MCU) controlling the switch control circuit toclose the first switch KEY1 and the second switch KEY2, such that thefirst battery set 11 and the second battery set 12 are connected inparallel, or to close the third switch KEY3, such that the first batteryset 11 and the second battery set are 12 are connected in series, and atthat time, the first battery set 11 and the second battery set 12 aredischarged;

S4, the main control chip (MCU) enabling the USB circuit, such that theUSB circuit outputs power to charge the external device;

S5, when the main control chip (MCU) detects no charging current in theUSB circuit, disabling the USB circuit;

S6, when the main control chip (MCU) detects that the charging currentof the USB circuit is greater than the certain value, enabling the USBcircuit and continuing detecting the charging current of the USBcircuit; and

S7, the first analog front-end 14 and the second analog front-end 15continuously monitor voltages of the first battery set 11 and the secondbattery set 12 in real time, and when the voltages of the first batteryset 11 and second battery set 12 are lower than a certain value, themain control chip (MCU) disabling the USB circuit to stop charging theexternal device and controlling the entire battery pack power supplysystem to shut down.

Of course, this embodiment may be used when the battery pack powersupply system is put into an electric tool, and may also be used whenthe battery pack power supply system is not put into an electric tool,and the USB circuit is used to charge an external device such as amobile phone; and after the battery pack power supply system is pluggedinto an electric tool, the extended power output interface 20 is readyfor charging an external device, and at the same time, the battery packpower supply system and the contact tab 40 of the electric tool abutagainst each other, to achieve series or parallel connection of thefirst battery set 11 and the second battery set 12, and at this time,the switch control circuit is disabled (i.e., automatically locked), andthe self-locking circuit causes a failure in the electronic switchesKEY1-KEY3 (i.e., the electronic switches KEY1-KEY3 are all opened).

The use of the self-locking circuitry protects the battery pack fromdamage. This is because the electronic switches KEY1-KEY3 are connectedin series or parallel, while the contact tab 40 of the electric tool isconnected in parallel or in series, and if the electronic switchesKEY1-KEY3 are not disabled, it will cause a short circuit of the twobattery sets. The self-locking circuit solves this problem because themoment the battery pack comes into contact with the contact tab 40, thecontact tab 40 disables the electronic switches KEY1-KEY3, such that theelectronic switches KEY1-KEY3 all enter a failure (opened) state, and nolonger operate, and the series and parallel connection of the firstbattery set 11 and the second battery set 12 is then only controlled bythe contact tab 40 of the electric tool.

In summary, on the one hand, with the USB circuit provided in thepresent disclosure, voltage step-down and current-limiting operationsmay be performed by the USB circuit on the voltage output from thebattery pack power supply system, such that the voltage after thestep-down and current-limiting operations may be used to charge theexternal device such as a mobile phone, so the battery pack may be usedin more scenarios; on the other hand, the self-locking circuit isprovided such that when the switch control circuit is disabled, theself-locking circuit can make the electronic switches KEY1-KEY3 fail andno longer controlled by the main control chip (MCU), thereby protectingthe entire battery pack power supply system.

While particular elements, embodiments, and applications of the presentinvention have been shown and described, it is understood that theinvention is not limited thereto because modifications may be made bythose skilled in the art, particularly in light of the foregoingteaching. It is therefore contemplated by the appended claims to coversuch modifications and incorporate those features which come within thespirit and scope of the invention.

1. A battery pack power supply system, comprising a first battery setand a second battery set; a switch control circuit connected withelectronic switches, to control the first battery set and the secondbattery set to be connected in series or in parallel; a main controlchip connected with the first battery set, the second battery set andthe switch control circuit, respectively, to control the electronicswitches to be open or closed to discharge the first battery set and thesecond battery set; a wake-up circuit connected with the main controlchip, to wake up the entire battery pack power supply system; a USBcircuit connected with the first battery set, the second battery set andthe main control chip, respectively, to output power for charging anexternal device under the control of the main control chip; and aself-locking circuit connected with the switch control circuit, todisable the electronic switches when the switch control circuit isprohibited.
 2. The battery pack power supply system according to claim1, wherein the electronic switches comprise a first switch, a secondswitch and a third switch, wherein when the main control chip controlsthe first switch and the second switch to be closed and the third switchto be open, the first battery set and the second battery set areconnected in parallel with each other; and when the main control chipcontrols the first switch and the second switch to be open and the thirdswitch to be closed, the first battery set and the second battery setare connected in series with each other.
 3. The battery pack powersupply system according to claim 1, further comprising a housing and acircuit board accommodated in the housing, wherein the first battery setand the second battery set are both accommodated in the housing, and theswitch control circuit, the main control chip, the wake-up circuit, theUSB circuit and the self-locking circuit are all formed on the circuitboard, wherein the housing is provided with an extended power outputinterface connected to the USB circuit and a cover plate for coveringthe extended power output interface, the cover plate being slidablyarranged to expose or cover the extended power output interface.
 4. Thebattery pack power supply system according to claim 3, wherein thewake-up circuit comprises a microswitch wake-up circuit, the microswitchwake-up circuit comprising a microswitch, wherein when the cover plateslides to expose the extended power output interface, the cover platesynchronously triggers the microswitch, such that the entire batterypack power supply system is woken up.
 5. The battery pack power supplysystem according to claim 3, wherein the wake-up circuit is a buttonedwake-up circuit, the buttoned wake-up circuit comprises a buttonprovided on the housing, and the entire battery pack power supply systemis woken up after the button is pressed.
 6. The battery pack powersupply system according to claim 1, wherein the USB circuit is providedwith a step-down component and a current-limiting component to performvoltage step-down and current-limiting operations on a voltage outputfrom the battery pack power supply system, and a voltage after thestep-down and current-limiting operations is output to charge theexternal device.
 7. The battery pack power supply system according toclaim 1, wherein the self-locking circuit is configured such that theswitch control circuit is not controlled by the main control chip whenthe switch control circuit is automatically locked.
 8. The battery packpower supply system according to claim 1, further comprising a firstanalog front-end connected in parallel with the first battery set and asecond analog front-end connected in parallel with the second batteryset, wherein the first analog front-end is connected with the maincontrol chip to collect a voltage of the first battery set and transmitthe voltage to the main control chip, wherein the second analogfront-end is connected with the main control chip to collect a voltageof the second battery set and transmit the voltage to the main controlchip.
 9. The battery pack power supply system according to claim 8,wherein when the voltages of the first battery set and second batteryset are lower than a certain value, the main control chip disables theUSB circuit in order to stop charging the external device and controlsthe entire battery pack power supply system to shut down.
 10. Thebattery pack power supply system according to claim 8, furthercomprising a communication isolation circuit, which is connected to thesecond analog front-end at one end and to the main control chip at theother end, so that the second analog front-end communicates with themain control chip in a bidirectional isolation manner through thecommunication isolation circuit.
 11. A battery pack power supply methodapplied to a battery pack power supply system, the battery pack powersupply system comprising a main control chip, a first battery set and asecond battery set, a switch control circuit, a wake-up circuit, a USBcircuit and a self-locking circuit, wherein the battery pack powersupply method mainly comprises the following steps: S1, inserting anexternal device USB charging cable into an extended power outputinterface of the battery pack power supply system, such that theexternal device USB charging cable is brought into electrical conductionwith the USB circuit of the battery pack power supply system; S2, thewake-up circuit waking up the entire battery pack power supply system;S3, the main control chip controlling the switch control circuit, suchthat the first battery set and the second battery set are connected inseries or in parallel, and the first battery set and the second batteryset are discharged; and S4, the main control chip enabling the USBcircuit, such that the USB circuit outputs power to charge an externaldevice.
 12. The battery pack power supply method according to claim 11,wherein the battery pack power supply system further comprises a housingand a circuit board accommodated in the housing, wherein the firstbattery set and the second battery set are both accommodated in thehousing, and the switch control circuit, the main control chip, thewake-up circuit, the USB circuit and the self-locking circuit are allformed on the circuit board, wherein the extended power output interfaceis provided on the housing and connected to the USB circuit; and thehousing is further provided with a cover plate for covering the extendedpower output interface, the cover plate being slidably arranged toexpose or cover the extended power output interface.
 13. The batterypack power supply method according to claim 12, wherein the wake-upcircuit comprises a microswitch wake-up circuit, the microswitch wake-upcircuit comprising a microswitch, and step S2 is specifically: when thecover plate slides to expose the extended power output interface, thecover plate synchronously triggering the microswitch such that theentire battery pack power supply system is woken up.
 14. The batterypack power supply method according to claim 12, wherein the wake-upcircuit is a buttoned wake-up circuit, the buttoned wake-up circuitcomprising a button provided on the housing, and step S2 furtherincludes: waking up the entire battery pack power supply system when thebutton is pressed.
 15. The battery pack power supply method according toclaim 11, wherein the switch control circuit is electrically connectedwith electronic switches, the electronic switches comprising a firstswitch, a second switch, and a third switch, wherein when the maincontrol chip controls the first switch and the second switch to beclosed and the third switch to be open, the first battery set and thesecond battery set are connected in parallel with each other, and whenthe main control chip controls the first switch and the second switch tobe open and the third switch to be closed, the first battery set and thesecond battery set are connected in series with each other.
 16. Thebattery pack power supply method according to claim 11, furthercomprising the following steps: S5, when the main control chip detectsno charging current in the USB circuit, disabling the USB circuit; andS6, when the main control chip detects that a charging current of theUSB circuit is greater than a certain value, enabling the USB circuitand continuing detecting the charging current of the USB circuit. 17.The battery pack power supply method according to claim 11, wherein theUSB circuit is provided with a step-down component and acurrent-limiting component to perform voltage step-down andcurrent-limiting operations on a voltage output from the battery packpower supply system, a voltage after the step-down and current-limitingoperations being output to charge the external device; and theself-locking circuit is connected with the switch control circuit, suchthat the switch control circuit is not controlled by the main controlchip when the switch control circuit is prohibited.
 18. The battery packpower supply method according to claim 11, wherein the battery packpower supply system further comprises a first analog front-end connectedin parallel with the first battery set and a second analog front-endconnected in parallel with the second battery set, wherein the firstanalog front-end is connected with the main control chip to collect avoltage of the first battery set and transmit the voltage to the maincontrol chip; and the second analog front-end is connected with the maincontrol chip to collect a voltage of the second battery set and transmitthe voltage to the main control chip.
 19. The battery pack power supplymethod according to claim 18, further comprising: step S7, the firstanalog front-end and the second analog front-end respectively detectingthe voltages of the first battery set and the second battery set in realtime, and when the voltages of the first battery set and second batteryset are lower than a certain value, the main control chip disabling theUSB circuit in order to stop charging the external device andcontrolling the entire battery pack power supply system to shut down.20. The battery pack power supply method according to claim 18, furthercomprising a communication isolation circuit, which is connected to thesecond analog front-end at one end and to the main control chip at theother end, so that the second analog front-end communicates with themain control chip in a bidirectional isolation manner through thecommunication isolation circuit.